docs: def check_metadata_link(self, ds):
          '''
          Checks if metadata link is formed in a rational manner
  
          :param netCDF4.Dataset ds: An open netCDF dataset
          '''
          if not hasattr(ds, u'metadata_link'):
              return
          msgs = []
          meta_link = getattr(ds, 'metadata_link')
          if 'http' not in meta_link:
              msgs.append('Metadata URL should include http:// or https://')
          valid_link = (len(msgs) == 0)
          return Result(BaseCheck.LOW, valid_link, 'metadata_link_valid', msgs)